Process for refining polymerized rosin



Patented Dec. 27, 1949 2,492,146 PROCESS FORREFININ G POLYMERIZED Burt L; Hampton, Jacksonville, Fla., assignor, by mesne assignments; to The Glidden Company, Cleveland, Ohio, a corporation of Ohio No Drawing. ApplicatlonFebruary" 23,1946;

. --..S.erial-No. 649376 'The' present invention relates to improvements in rosin and particularly relates to a process for; upgrading and refining polymerized rosin.

In the joint application SerialNum'ber 431,836" fi ed February 21, 1942, now" abandoned, in which I am one of the joint inventors, it was disclosed that when rosin is heated in the presence of small amounts of selenium, from;.0l to 1.0%, the prod uct is stabilized against. oxidation and also the product is lighter in color than the starting rosin. The present invention is an: extension oi the joint teaching thereof..

An object of thepresent invention is. toprovide a process of improving polymerized rosin.

Another object is to provide aprocess for upgradin polymerized rosin.

A further object is to. produce a polymerized f rosin of improved grade which does not show fluorescence or bloom.

I have now found that if rosin-which has been polymerized is heated with small amounts of. selenium, the color of the rosin is improved. Fur: thermore, I'have found that this heat treatment, with seleniumstabilizes the polymerized rosin .be-. yond that which is effected in the ordinary poly.- merization process. Such stabilization, is believed .2 to result from aromatizationv of not jsubstantiall'y more than one ring of some ofthe polymerized: rosin molecules as welljas .from similar aromatizae tion of unpolymerizedrosin contained ..in ,.the.; polymerized material. I prefer to carry out the. selenium treatment in the presence. of small amounts of added acid, either organic or inor-g ganic, which is stronger than abieti'c' andother rosin acids, as this treatment prevents fldor.es-, cence or bloom caused by the seleniumtreatment if the. polymerized rosin contains metals. Where the polymerized rosin is free of metals, this acid treatment may not be required to prevent bloom, but,nevertheless, it is good practice to employ such treatment'if .freedom fr'om...bloom is desired, especially when the treatment is beingcar- ,1 ried out in a metal receptacle. The presence. oil the 'acid,however, does not seem to'aid the sele nium decolorization.

The temperatures employedi'may vary ovenaa considerable range. Below about. 25.0.? CI, how-e. ever, the action is slow, while the-temperatures; above 350 C. are apt to cause excessive decalboxylation, and. therefore should generally. beavoided. Also the decolorizing action of'the selenium may be nullified "byexcessivegheating at; higher temperatures. Preferred temperatures"; are from "about 260 C. to 310 C." Itisalso pres ferred in practice to carry outithe"heatingmith se'leniumain :twoostages'; Inwthe-rfirst-zstageethe reactionv mixture is. heated in the absence ofizanyi sparging gases. In the second stage the heating":- is continued at temperatures ranging from about 25 O, C..to.abo.ut 285 C... and steamer other inert sparging gas islpassed' through the reaction mixture .to remove volatile reaction products. In. some instances'it is beneficial .to provide an .inert atm0sph'ere, .such as carbon dioxide, during the first stage, and" also ,while .cooling .theproduct after the second stage. Aninert atmosphere dur-" ing the second stage isunnecessary because the spargingagases and the volatile+productsaof reaction: provide adequate portection.

,jThe; amounts of selenium required to produce.- improvementim color are -quite+smalh Amounts ofsifromilllll to ,1-.0-%-,may be -used but it nas been"? found that. amounts of-rf-rom ..0.5 to: 0.3% are tc-rbe a preferred generally. Infiplaceiof free selenium;.- selenium compounds. suchas selenium dioxide or selenium halides, which form free selenium during the :treatment'may be-usedfi When selenium halides are used sma ller amounts of added acid may be used,'sif at all.

'lh'e time on the heating mayalso vary.- Gen-* erally, from'one-"half to 7 three hours is 'su'fficienti for the first stage treatment. The time, of course, is somewhat dependent upon the amount of selenium and the-te'mperature.-- The time, however, should not be so long as to cause-excessivedecarboxylation under the other'conditions "existing. It shouldals'o be -kept-in mind that when-the sparging treatment isemployed; as a second stage,- some of the volatileproducts contain selenium and that during this sparging operation the sele nium is graduallyrbeing:removed. Fifteen to thirty minutes is generally sufficient for the sparging treatment, althoughiitmayfbe longer or shortenwr' eliminated altogether if desired.

In general,the minimum'oVer-alltime for the treatment including any sparging shouldbe at least about thirty minutesat the preferred temp eratures,..the maximum, .of course, being that whiclrpro'duces undesired decarboxylation';

1. Among the. acids" which are stronger th'anrosin acids and Whic'hmay consequently be'usedherein, may be mentioned phosphoric, acetic, sulfuric,- stearic, formic, hydroehloricaand oxalic. The amounts requiredhare quite .small, 5% of acid wea'ks acids, such. as stearic, propionic, malonic, and theilike; and'lesser amounts-being sufiic'ient. for-stronger acids. 1 From10l18 %1 to .015 oisuch strong racids" aaphosphorim.sulfliric,..hydrochlorlc is generally adequate while from .1%-to,,.4% of.

by. weight crane. rosin beingsufii'ientfor thevery Polymerized rosin of grade N, M. P. 100 C. (R. 8: B.) and A. N. 154, was heated with 0.15% selenium at 270-278 C. for one hour and then steamed at 265-275 C. for twenty minutes, after which the mass was cooled to 210 C. while continuing the steaming. The product graded X, had a melting point of 94 C. and an acid number of 146.

EXAMPLE II K grade polymerized rosin, M. P. 95 C. and A. N. 152 was heated with 0.15% selenium at 275-285 C. for one hour and steamed gently at 265-275 C. for thirty minutes and cooled to 180 under carbon dioxide to give a product of WG grade, A. N. 144 and M. P. 90 C.

EXAMPLE III N grade polymerized rosin, M. P. 100 C., A. N. 154 was heated to about 200 C. and 0.2% selenium and about 008% of 85% phosphoric acid added. The reaction mass was then heated at 275-280 C. for one hour and steamed at 270-280 C. for thirty minutes to give a product of WW to X grade, A. N. 152, and M. P. 96.

EXAMPLE IV I grade polymerized rosin, M. P. 100 C., A. N. 155 was heated at 275-285 C. for one hour with 0.2% selenium and about .008% of 85% phosphoric acid, and then steamed at 275285 C. for thirty minutes. Grade N, M. P. 98 C.; A. N. 146.

EXAMPLE V N grade polymerized rosin, M. P. 102, A. N. 144, was heated to about 200 C. and 0.10% selenium was added to the molten resin which was then heated to 275-285 C. for one hour and then steamed at this temperature for thirty minutes. The product grade WW, M P. 94 C.; A. N. 137; and (alpha)o+17.

EXAMPLE VI The procedure was the same as in Example V except that about 0.008% of 85% phosphoric acid was added. The product graded WW, A. N. 136, M. P. 95, (alpha)n+13.

EXAMPLE VII The procedure was the same as an Example V except that the amount of selenium was reduced to 0.05%. The product graded WG; A. N. 138; M. P. 99.5; (a1pha)r +7.

EXAMPLE VIII Tall oil may be used. I

I A polymerized rosin available whether it The increased severity of the selenium treatment in this sample resulted in somewhat increasing the positive optical rotation of the product, thereby indicating greater stability, but the increase was not as great as in the case of unpolymerized rosin treated similarly.

EXAMPLE IX grading N-WG, A. N. 133, M. P. 106.5, was heated with .15% selenium at 290-295 C. for thirty minutes and then steamed for twenty minutes. The product graded WW; A. N. 129; M.P.

EXAMPLE XI N grade polymerized rosin, M. P. 118.5, A. N. 132, prepared from a WG gum rosin, Was divided into various portions and each subjected to a different heat treatment with .15% selenium. Each portion was steamed at 265-275 C. for thirty minutes, following the indicated heat treating. The variations in the procedure and product are shown in the table.

Table Temp. of Expeu 0 Time of Percent ment Heatin Heating HsPO4 G1 ade A. N. M. P

1 275-285-. 1 hr..." None W'W 130 116 2 275285 1 hr .008 WW 109 3 275-285 30 min.. None WW- 110.5 4 293300 1 hr None WW 127 111 It will be readily apparent from the foregoing examples that the treatment of polymerized rosin according to the present invention results in con siderable upgrading of polymerized rosin. The

polymerization procedures which are ordinarily 40 employed result in a considerable lowering of the grade and it is known that in all of the foregoing examples, except Example IX, the undisclosed polymerization procedures did result in a lowering of the grade. However, in all instances the.

products resulting from the herein described treatments were lighter in color than the original polymerized rosin and at least as light as the unpolymerized rosin from which was obtained the polymerized rosins. Thus the present invention makes it possible to produce a polymerized rosin of at least as high a grade as the original rosin.

In the following claims the term free selenium is used to refer to the selenium which is for the herein disclosed purposes is elemental selenium or is derived from selenium compounds.

Having described the invention, what is claimed is:

1. The process for refining polymerized rosin which comprises heating a polymerized rosin with from 0.01 to 1% of free selenium at a temperature of 250 to 350 C. for a time of at least about thirty minutes but insufiicient to cause substantial decarboxylation.

2. The process for refining polymerized rosin which comprises heating a polymerized rosin with from 0.01 to 1% of free selenimn at a temperature of 260 to 310 C. for from thirty minutes to three hours.

3. The process for refinin polymerized rosin which comprises heating a polymerized rosin with from about 0.05% to 0.3% of free selenium at a temperature of 260-3l0 C. for from thirty minutes to three hours.

4. The process for refining polymerized rosin which comprises heating a polymerized rosin with from .01 to 1% of free selenium and with a small amount of acid stronger than abietic acid at a temperature of 250 C. to 350 C. for a time of at least about thirty minutes but insufiicient to cause substantial decarboxylation.

5. The process for refining polymerized rosin which comprises heatin polymerized rosin with from .01 to: 1% of free selenium and with a small amount of acid stronger than abietic acid at a temperature of 260 to 310 C. for from thirty minutes to three hours.

6. The process for refining polymerized rosin which comprises heating polymerized rosin with from .05 to 0.3% of free selenium and with a small amount of acid stronger than abietic acid at a temperature of 260 to 310 C. for from thirty minutes to three hours.

7. The process of claim 1 which includes the additional step of sparging the treated rosin with steam at temperatures of between about 250 C. and 285 C. for about thirty minutes.

8. The process of claim 2 which includes the added step of sparging the treated rosin with steam at temperatures of between about 250 C. and 285 C. for about thirty minutes.

9. The process of claim 3 which includes the added step of sparging the treated rosin with 6 steam at temperatures of between about 250 C. and 285 C. for about thirty minutes.

10. The process of claim 4 which includes the added step of sparging the treated rosin with steam at temperatures of between about 250 C. and 285 C. for about thirty minutes.

11. The process of claim 5 which includes the added step of sparging the treated rosin with steam at temperatures of between about 250 C. and 285 C. for about thirty minutes.

12. The process of claim 6 which includes the added step of sparging the treated rosin with steam at temperatures of between about 250 C. and 285 C. for about thirty minutes.

BURT L. HAMPTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,492,146 December 27, 1949 BURT L. HAMPTON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 4, in the table, last column thereof, for 110.5 read 119.5;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 11th day of April, A. D. 1950.

TIIOM AS F. MURPHY,

Assistant Commissioner of Patents. 

